Bra Size Calculator
Find your accurate bra size with our easy-to-use calculator.
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Bra Size Calculator: Find Your Perfect Fit Instantly
An advanced tool to find your accurate bra size in US, UK, EU, and other international systems.
Includes sister sizes and a comprehensive guide to getting the right fit.
Finding the perfect bra is a transformative experience, yet studies show that over 80% of women are wearing the wrong bra size. An ill-fitting bra can cause discomfort, back pain, poor posture, and even affect your confidence. The world of bra sizing, with its confusing numbers, letters, and international variations, can feel overwhelming. Manual measurements often lead to incorrect sizes, perpetuating the cycle of discomfort.
Welcome to our Bra Size Calculator, a free, advanced online tool designed to demystify the process and guide you to your most accurate fit. This is more than just a simple measurement tool; it's a comprehensive resource that provides your US/UK size, a detailed international bra size conversion chart, and an explanation of "sister sizes" to give you more options when shopping. This guide will walk you through how to use our calculator, explain the science of bra fitting, and provide expert tips for finding comfort and support.
How to Use Our Bra Size Calculator: A Simple 2-Step Process
Our calculator is designed to be fast, accurate, and easy to use. The results update automatically as you enter your measurements, providing instant feedback.
- Select Your Measurement Unit: At the top, choose whether you are entering your measurements in Inches (in) or Centimeters (cm).
- Enter Your Measurements:
- Band Size (Underbust): Measure snugly around your ribcage, directly underneath your bust. Make sure the tape measure is level and parallel to the floor. Enter this number in the first box.
- Bust Size (Fullest Part): Measure around the fullest part of your bust, typically across the nipples. The tape should be firm but not tight. Enter this number in the second box.
- Instantly View Your Results: As soon as both fields are filled, the calculator will immediately display your calculated bra size, your sister sizes, and a comprehensive international conversion chart.
This streamlined process ensures you can quickly and accurately find your bra size without any complicated steps. Keywords: bra fitting calculator, online bra size measurement.
Understanding Your Results: More Than Just a Size
Our calculator provides a wealth of information to help you find the perfect fit. Here’s a breakdown of what each part of the result means.
Your Calculated Bra Size
This is your recommended starting size based on the standard US/UK sizing system. It consists of a number (the band size) and a letter (the cup size).
Your Sister Sizes
This advanced feature provides alternative sizes that have the same cup volume. If your calculated size doesn't feel right, a sister size might be the perfect fit. For example, a 34C has the same cup volume as a 32D and a 36B.
International Size Chart
Bra sizing is not universal. Our bra size conversion chart translates your US/UK size into its equivalent in other major sizing systems, including Europe (EU), France/Spain (FR/ES), and Australia/New Zealand (AU/NZ).
The Science of Bra Sizing: How Are Sizes Calculated?
Understanding how bra sizes are determined can empower you to make better choices when shopping. The calculation involves two key components: the band size and the cup size.
1. Determining Your Band Size
The band provides the majority of the bra's support (around 80%). The number in your bra size (e.g., 34C) refers to your band size. Our calculator uses the standard "Underbust + 4" method, which is widely used by many brands.
Formula:
- Measure your underbust (ribcage) in inches.
- Add 4 inches to this measurement.
- If the result is an odd number, round down to the nearest even number. This is your band size.
Example: If your underbust measurement is 30 inches, you calculate 30 + 4 = 34. Your band size is 34.
2. Determining Your Cup Size
The cup size represents the volume of your bust in relation to your band size. The letter in your bra size (e.g., 34C) is your cup size. It's calculated by finding the difference between your bust measurement and your calculated band size.
Formula: Cup Difference = Bust Measurement (in inches) - Calculated Band Size
Each inch of difference corresponds to a letter in the alphabet:
| Difference | Cup Size |
|---|---|
| 0 inches | AA |
| 1 inch | A |
| 2 inches | B |
| 3 inches | C |
| 4 inches | D |
| 5 inches | DD (E in UK) |
| 6 inches | DDD (F in UK) |
Our cup size calculator automates this entire process to give you an accurate starting point.
The Secret to a Perfect Fit: Understanding Sister Sizes
One of the most valuable but least-known concepts in bra fitting is "sister sizing." Sister sizes are groups of bra sizes that have the **same cup volume**. This is an incredibly useful trick for finding a comfortable fit when your standard size isn't quite right.
The Rule is Simple:
When you go UP one band size, you must go DOWN one cup size to maintain the same cup volume. When you go DOWN one band size, you must go UP one cup size.
For example, the following sizes all have the same cup volume:
32D = 34C = 36B
Our calculator automatically provides your two closest sister sizes. Here’s how to use them:
- If the band of your 34C bra feels too tight, but the cups fit perfectly: Try your sister size with a larger band, which is a 36B.
- If the band of your 34C bra feels too loose, but the cups fit perfectly: Try your sister size with a smaller band, which is a 32D.
Navigating the World: The International Bra Size Chart
Shopping for bras online or while traveling can be confusing because sizing is not standardized globally. Our bra size conversion calculator solves this problem by providing a detailed chart that converts your US/UK size to other major systems.
- US/CA (United States/Canada): Uses the standard inch-based system.
- UK (United Kingdom): Similar band sizing to the US, but cup sizes diverge after DD (UK uses E, F, FF, G, etc.).
- EU/INTL (Europe/International): Uses centimeters for band sizing (e.g., 75, 80, 85).
- FR/ES/BE (France/Spain/Belgium): Uses a system where the band size is 15 cm larger than the EU size.
- AU/NZ (Australia/New Zealand): Uses a dress-size system for the band (e.g., 10, 12, 14).
This feature makes our tool a true international bra size calculator, essential for any global shopper.
Frequently Asked Questions (FAQ)
- The band is snug and level around your back (not riding up) and provides most of the support. You should be able to fit two fingers underneath it comfortably.
- The cups fully contain your breast tissue without any spilling over the top or gaps at the sides.
- The center gore (the part between the cups) sits flat against your sternum.
- The straps sit comfortably on your shoulders without digging in. They should provide only about 20% of the support.
Conclusion: Your First Step to Comfort and Confidence
Finding the right bra size is a crucial act of self-care. Our Bra Size Calculator is designed to be your trusted first step in this journey. By providing an accurate starting size, a useful international conversion chart, and the invaluable concept of sister sizes, this tool empowers you with the knowledge needed to shop with confidence.
Say goodbye to uncomfortable bras and the confusion of sizing charts. Use our free, comprehensive calculator today to find your perfect fit and experience the difference that true comfort and support can make.